The present invention relates to a valve arrangement with a main shifting valve and a pilot control valve, whereby a valve member of the pilot control valve movable between two valve seats is adapted to be sealingly pressed against one valve seat by means of a plunger externally actuatable, for example, by electromagnets and thereby closes off a connection of an inlet line with a control pressure space which is opened up when placed against the other valve seat as well as opens up a connection between the control pressure space and a return line which is closed off when placed against the other valve seat.
Such a valve arrangement is the subject of the DE-PS No. 29 38 100. The pilot control valve can be actuated with very small forces, and more particularly also when the main shifting valve is to control a large opening cross section with high pressure differences between inlet and outlet side of the valve arrangement.
However, the valve arrangement illustrated in the DE-PS No. 29 38 100 is less suited for the use of hydraulic shifting arrangements which possibly must consist of several such valve arrangements because in such a case the lines to be provided between the valve arrangements are difficult to install.
It is known from the DE-OS No. 22 60 938 to construct a valve unit in such a manner that all line connections are arranged on one end face of a socket or the like. However, the DE-OS No. 22 60 938 relates to a valve arrangement which differs pronouncedly from a constructive point of view so that no further suggestions are provided therein as regards the construction of a valve arrangement of the first-mentioned type.
A valve subassembly is described in the DE-OS No. 31 30 581 in which a valve ball cooperates with two valve seats arranged coaxially to one another, which are adjoined by lines controlled by the valve ball. One valve seat is thereby arranged at the bottom of a cup-like housing whereas the other valve seat is provided at a valve seat part which is inserted into the open end of the cup-like housing in the manner of a plug The connections of the valve subassembly are arranged at the circumferential wall of the cup-like housing, at the end face bottom thereof as well as at the valve seat forming the other housing end face. As to the rest, the valve ball is controlled directly, i.e., not by means of a pilot control valve.
The DE-PS No. 31 10 839 relates to a closure valve in which inlet and outlet lines terminate on the same side in a chamber whose oppositely disposed side is formed by a diaphragm which can be pressed onto the orifice of the outlet line by means of a plunger or the like in order to interrupt the connection of inlet and outlet line by way of the chamber.
It is now the object of the present invention to provide a valve arrangement of the aforementioned type whereby, on the one hand, a particularly simple construction and, on the other, the possibility of a simple integration into hydraulic shifting arrangements is to be made possible.
The underlying problems are solved according to the present invention in that the inlet, outlet and return lines are arranged extending through a socket part of the valve arrangement and terminating at the same end face of the socket part, in that the socket part has a cup-like recess at its end face opposite the orifices in which terminate the inlet and outlet lines on the bottom side, whereby the seat of the main shifting valve is arranged at the orifice of the outlet line, in that the valve housing part is inserted into the cup-like recess in the manner of a plug while leaving free an intermediate space, in that the valve seat part rests on the end face of the valve housing part opposite the bottom of the cup-like recess in the manner of a cover and holds fast at the facing circumferential edge of the valve housing part a sealing ring sealing the valve housing part in the cup-like recess, and in that a sleeve member surrounding the socket part is arranged at the latter under formation of an annular space which, on the one hand, is connected with the return line and, on the other, with a space present on the end face of the valve seat part opposite the valve housing part which space is connected with the chamber by way of the opening adjoining the valve seat in the valve seat part.
A particularly simple type of construction is achieved by the present invention. The sleeve member surrounding the socket part can secure directly or indirectly the position of the valve housing part as well as of the valve seat part in, respectively, on the cup-like recess of the socket part. The sealing ring held fast by the valve seat part at the circumferential edge of the valve body member facing the valve seat part can seal, on the one hand, the annular gap between the valve housing part and the circumferential wall of the cup-like recess and, on the other, also the gap plane between the valve housing part and the valve seat part. As to the rest, the sleeve member can also retain an electromagnet or another actuating device for the valve arrangement.
In particular the possibility is created by the present invention to arrange the socket part on a line plate and to connect the inlet, outlet and return lines with lines extending within the plate in that openings, respectively, orifices of the plate-side lines which correspond with the orifices of the inlet, outlet and return lines, are provided at the fastening locations of the socket on the plate.
According to a preferred embodiment of the present invention, the end face of the sleeve member opposite the socket can be closed off by means of a diaphragm whose edge is sealingly clamped-in between a ring-shaped collar arranged at the sleeve member and an intermediate member which supports the valve seat part axially on the collar.
The intermediate member may be provided with a bore for the guidance of a plunger member whose one end cooperates with the valve member of the pilot control valve and whose other rounded-off, respectively, mushroom-head-like end abuts at the diaphragm so that the plunger member is adjustable by pressure on the diaphragm.
The diaphragm is practically not acted upon by any significant pressure forces if a line is arranged in the intermediate member which connects a space remaining between the diaphragm and the intermediate member within the area of the plunger member with the space connected with the return line on the side of the valve seat part opposite the valve housing part.
The sleeve member, respectively, the ring-shaped collar arranged thereat may carry the electromagnet having a core, respectively, adjusting member coaxial with the plunger member.